In an inner-rotor type molded motor, a rotor has its outer shell, which is made of a molded resin, arranged on the inner diameter side of a molded stator. The rotor rotates with the output side and counter output side of its output rotary shaft supported by bearings. The bearings are accommodated in bearing houses formed in brackets arranged on the output side and the counter output side of the outer shell of the stator.
Here, if there is a difference in potential between the bracket on the output side and the bracket on the counter output side, a current flows in the bearings to cause electric corrosion. The electric corrosion induces the vibration and noise of a motor. As an example of preventing electric corrosion, a molded motor has been known in which electrical continuity between a bracket on an output side and a bracket on a counter output side is established by a conductive tape attached to the side surface, i.e., the outside, of a mold (see, for example, Japanese Patent Laid-Open No. 2007-20348 (in paragraph [0019] on page 4 and FIG. 1)).
However, since the conductive tape is attached to the outside of the mold, the electrical continuity between the bracket on the output side and the bracket on the counter output side may be interrupted when the conductive tape is peeled off or cut off at assembling, integration into a product, shipment, maintenance, temporal change, or the like of the molded motor.
Accordingly, the present invention has been made in view of the above problem and is thus directed to provide a molded motor that hardly causes electric corrosion in bearings and produces less noise and vibration.